Scenery handling apparatus



July 11, 1961 J. F. KUEBLER SCENERY HANDLING APPARATUS 2 Sheets-Sheet 1 T' ZJ- INVENTOR J5me: 54 1/5545? BY m ww ATTOR E A i foummewewyr Filed May 5, 1959 T 1:.l.

United States I rent 2,991,526 SCENERY HANDLING APPARATUS James F. Kuebler, 194 Riverside Drive, Tiflin, Ohio Filed May 5, 1959, Ser. No. 811,131 '17 Claims. (CL 2'4--126) This invention relates to rope-locking devices such as are used to clamp hand-operated control ropes for raising or lowering draperies or scenery on a stage. More in particular, this invention relates to a rope-locking device adapted automatically to prevent release of the control rope when more unbalanced tension exists in the rigging system than the operator can manually overcome.

For raising or lowering scenery and the like on a stage, it is usual practice to provide a system of running lines (generally steel cable) which extend from the top of the scenery through a pulley system leading to an operating station at one side of the stage, and the operation of the system is through means of a manila or nylon control rope at the operating station. Typically the scenery is very heavy, and to make it possible to fly or bring-in the scenery by hand the system generally includes counterweights to maintain a balanced tension throughout the running lines. Thus the operator (flyman) of the control rope need only overcome friction and inertia in order to raise or lower the scenery.

In many installations there are a substantial number of running line systems with their respective individual control ropes leading to the operating station and means are provided at this station to lock each control rope with the scenery at any selected elevation. Conventionally 20 or 30 or more control ropes might lead down side by side to the operating station, each leading through a separate locking device attached to a fixture such as a locking rail anchored to the stage floor or fly floor.

Very often, such as during preparations for a play or other events on the stage, it is necessary to make changes to the scenery suspended from various counterweight systems as by removing equipment (drapery, track, scenery, lights, etc.) from a system and attaching others or by removing equipment and allowing the system to remain empty. In making such changes, the counterweights often must be altered in quantity because the weight of the new equipment is different from that of the old or because the system is allowed to remain empty. At times, errors or misjudgments are made in selection of the quantity of counterweights to be loaded or unloaded from the system or the counterweights are purposely left off for short periods of time. Thus through inadvertence or otherwise, an unbalanced system frequently exists with only the locking device on the control rope holding the unbalanced system static.

Such an unbalanced system will cause no difiiculty as long as the control rope is locked in place at the operating station. However, if the rope-locking device is accidentally released, the unbalance in tension can cause the scenery or the counterweights to come crashing down with possible serious injury to life or expensive equipment. The extent of damage could be considerable because the counterweights may weigh as much as 500 pounds or more, and the drop distance for the scenery or the counterweights might be as much as 70 feet. With priorstage-rigging equipment such accidental release of a control rope can readily occur, particularly when the controls are being operated by inexperienced persons such as school-children. The present invention is directed to solving this and related problems.

In an embodiment of this invention, to be described hereinbelow in detail, there is provided a rope-locking device having releasable gripping means to hold a rope by friction, and spring-urgedpressure'means arranged normally to maintain the gripping means engaged with the rope. When the tension on the rope is balanced, arelease mechanism is operable to disengage the gripping means so that the rope may be shifted through the device by hand. However,,when an unbalanced tension exists, a safety mechanism in the device automatically disables the release mechanism to prevent disengagementof the gripping means.

Accordingly, it is an object of this invention to provide a rope-locking device that is superior to such devices provided heretofore. It is a further object of this invention to provide such a device that will maintain a grip on the rope as long as there is an unbalanced tension in the counterweight system. It is a still further object of this invention to provide such a device which is automatic in operation, and which includes safety features to prevent inadvertent operation or tampering by unauthorized personnel. Yet another object of this invention is to provide such a device that is simple in operation and economical to manufacture. Other objects, advantages and aspects of the present invention will be in part apparent from, and in part pointed out in, the following description considered together With the accompany- FIGURE 3 is a vertical section taken along line 33' of FIGURE 2;

FIGURE 4 is a vertical section taken along line 4-4 of FIGURE 2, showing certain details of the release mechanism;

FIGURE 5 is a vertical section taken along line 5-5 of FIGURE 2, showing the vertically-movable wedge member and associated parts;

FIGURE 6 is a cross-section taken along line 6-6 of FIGURE 2 to show certain aspects of the rope-gripping elements and the control mechanisms; and

FIGURE 7 is a perspective view showing the ropegripping elements.

Referring now to FIGURE 1, the illustrative embodiment of the invention comprises a shell or casing 10 anchored to a locking rail 12. As shown in FIGURE2,

' within this shell is a rope braking and locking unit 14 and control and operating mechanism designated generally at 16. The rope braking and locking unit includes gripping means comprising an anvil 18 and a mating shoe 20 (see also FIGURE 7) formed respectively with opposed cylindrical recesses "22, 24 arranged to fit about and grip the rope 26.

The shoe 20 is slidably mounted Within bifurcated extension 28, 30 at the respective ends of the anvil 18, and slides to the left or right (FIGURE 2) to increase or decrease the pressure on the rope. The shoe is urged to the right, away from the anvil and rope, by springs 32, 34 which extend between respective cross-pieces 3 6, 38 at the ends of the anvil and respective end flanges 40, 42 forming part of the shoe. As will be explained, the shoe normally is forced tightly against the rope to frictionally engage the rope so as to prevent it from moving through the rope-locking device.

The right-hand face of shoe 20 is formed with two pairs of cam surfaces 44, 46 and 48, 50 which serve as dwells for a respective pair of pin-bar rollers 52, 54. Each of these cam surfaces is at an angle of 14 degrees to the vertical, i.e. 14 degrees to the axis of rope 26 where it passes through the rope-locking device. 52, 54 are rotatably secured within the interior of an elongated cam member 56 which comprises a pair of Rollers parallel plates 'having three "spacer elements 57 therebetween. This cam member is slidably mounted between upper and lower guide strips 58, 60 and floats between the shoe and a vertically-shif table wedge member 62. The cam member and wedge member are provided with mating cam faces 64, 66, respectively, both at an angle of 4 /2 degrees to the vertical.

Referring to FIGURES and :6, wedge member 62 comprises a pair of parallel side plates '68, 70 between which is positioned a vertical guide rod 72 extending down to the lower guide strip 60. This wedge member also includes two guide blocks 74, 76 mounted between the side plates 68, 70. These blocks are fo ed with bores through which guide rod 72 ex commodate vertical sliding movernferit ber along the rod. i i

Within the wedge member 62, spamm n guide rod 72, is a compression spring 78 heibwe'i end of which engages a collar 80 fixed 'to the 1 The upper end of this spring engages another fco l lar 82 "is s'lidably mounted on the rod and whichpresses 'against the upper guide block 74. Hence ne weagemem'ber is urged upward by spring 78, its motion Being limited by a pair of stop pins 84, 86 secured to the shell and extending into slots 88, 90 formed in the side plates 68, 70 of the wedge member. The upward pressure on this wedge member normally forces cammember 56 and shoe to the left, so that the shoe grips the rope tightly to hold it securely in place.

The lower guide block 76 of wedge member 62 extends out to the right (FIGURE 2) to form a bracket 92 which is provided with 'a vertical bore to receive an operating rod 94. This rod extends up through a locking block 96 (FIGURE 4) immediately above the bracket. The locking block is formed at its top and bottom with respective cylindrical. recesses 98,100 separated by a horizontal wall 102 which is formed with a bore for the operating rod. i i

Within the lower recess 100 is as'pring104 surrounding the operating rod 94. The lower'end of this spring engages the wedge member bracket 92, while its upper end presses against the locking block wall 102 so as normally to urge this block upwards away from the bracket. Within the upper recess 98 'is another spring 106 which alsosurrounds operating rod 94. The upper end of this spring engages an adjustment nut 108- threaded on the operating rod, while the lower end of this spring engages a collar 110 slidably mounted on the rod and seated against wall 102. Thus the operating rod is urged upwards by spring 106.

Secured in one side of the shell 10 is a key-operated lock mechanism 112 having a plunger 114 'engageable with a hole in the side of the locking block 96. This mechanism is of conventional construction wherein the plunger may be extended into the hole (as shown in the durawings) by manually pressing the mechanism from outside the shell. The plunger may be retracted by insetting a key which, when turned, releases the plunger so that it may be withdrawn by means of the usual spring action within the lock mechanism. By this means the locking block may be fixed in position so as positively to prevent release of the rope-lockingdevice as will be explained below.

To assure that the locking block normally will be in correct position to receive the plunger 114, the operating rod 94 is formed with a shoulder 116 adapted to engage collar 110, and the upper spring 106 is made substantially stronger than the lower spring 104. With this arrangement the lower spring will move the locking block 96 only up to the point where the wall 102 is flush with shoulder 116 on the operating rod 94, i.e. in position (as shown) to be locked by the mechanism 112. The locking block cannot be moved any further upward by lower spring 104 because at this point upperspring 106 becomes effective to overcome the force of the lower spring;

The operating rod 94 is mounted for vertical movement through an opening 118 in the lower guide strip 60, and is provided with a stop collar 120 to limit upward movement. The bottom of the operating rod is formed with an eye 122 to which secured a pull-rod 124 (FIG- URE 1) having a foot-stirrup 1:26 attached to its lower end. When a person steps on the foot-stirrup, the resulting downward motion of the operating rod tends to compress upper spring '106 which thus applies a corresponding downward force to the locking block 96.

For reasons which will be explained below, when the tension in rope 26 is in balance'pthelocldn'g block 96 and the bracket 92 are free to move down under the increased pressure produced by operation of stirrup 126, these elements being guided in this movement :bystrips I27, 128, 129 (see also FIGURES? and 6) secured to the right-hand portion of shell '10. When the bracketmoves' down, it carries with it wedge member '62 (FIGURE 2) so that cam member 56 and shoe 20am free to move a small distance to the right under the action of springs132, 34. Hence, under these conditions the anvil 18 and shoe 20 no longer will grip the rope 26 which thus may be shiftedmanually through the gropelocking device. The pull-rod 124 is of such a length that the foot-stirrup 126 reaches the floor when the grip on the rope has been fully released. This the operator can stand firmly on both feet and manipulate the rope while maintaining the rope free of the grip of the inciting device.

The rope-locking device disclosed herein also includes means for preventing release of the rope whenever an unbalanced tension exists in the counterweight system. For this purpose, as shown in FIGURE '2. the anvil 18 is mounted for ve'rti'cal movement on acontrol rod 130 whichis secured to a base member 132 and extends through a bore 134 formed the anvil. A pair of rollers 136, 138 alsoengage theleft hand face of the anvil to accommodate vertical rnovem'ent. The lower end of bore 134 is counter @lffid at 140 to receive a spring 142, the top of which s eats against the ledge at the end of the counter-bore and the bottom of which seats against an abutment member 144- forming part of anvil 18. A second spring 146 is positioned between members 132 and 144 to apply an upward pressure on the anvil in opposition to the downward pressure of spring 142. Thus the anvil and shoe are floated by these two springs 142, 146 against the action of gravity so as normally to maintain the anvil and shoe in the position shown.

When the anvil 18 and shoe 20 are clamped to the rope 26 and an unbalanced tension is applied to the rope, the anvil and shoe will move vertically (either up or down, depending upon the direction of unbalance of this tension). This vertical movement is guided by a pair of pins 148 (see also FIGURE 6)"se'cu red to opposite sides of shell 10 and extending int o corresponding slots 150 in the anvil. When the shoe moves vertically, its cam surfaces 44, 46 and 48, 50 apply pressure to rollers 52, 54 and apply a force to cam member 56 tending to move this member to the right. This jams'the'wedge member 62 tightly in position between the cam member and the locking block 96, and increases the gripping pressure applied by the anvil 18 and-shoe 20 to the rope.

Thus, when the operating rod 94 subsequently is moved down by the foot stirrup 126, the upper spring 106 will merely be compressed ag'ainst'thelockingblock 96 since this block and wedge member 62 cannot then move down because of the pressure of cam member 56. In that event, the gripping pressure-applied by the anvil 18 and shoe 20 to the rope 26 will not be released and the rope cannot be shifted through the rope-locking device. It will be apparent that the rope similarly will be held fixed in position whenever the lockingblockis secured against vertical movement by the plunger 114 of the keyoperated mechanism 112. I i

From the above ;desc1 ip y t p n the s t attest ng r a e action f the gripping means will become effective unless the system is in balance or until any unbalanced condition is overcome. If the unbalance in tension on rope 26 is not very great, the operator can release the rope by stepping on the foot stirrup and then pulling on the control rope in a direction to rebalance the tension. Thus with any unbalance overcome the rope can be payed out by hand as long as the operator keeps the foot stirrup depressed.

If after the rope has thus been released, it is found that the unbalance in tension is too great for the operator to control properly he need only lift his foot from the foot-stirrup and the rope-locking device again will clamp the rope securely in position. This latter feature provides an effective failsafe arrangement since, if the released rope gets out of control, the operators natural instinct would be to step back away from the rope-locking device and thereby relock the rope in a fixed position. In practice any counterweight system thus indicated to have unbalanced tension of sufficient magnitude to cause the operator more than comfortably safe effort for release and manipulation of the controlrope should be rebalanced by loading or unloading the proper quantity of counterweights. It is also to be noted that both hands of the operator are free to grasp the control rope for overcoming any unbalanced condition while the locking and unlocking cycle are occurring. This compares with existing equipment where one hand must be immobilized to operate the rope lock lever with the resulting possibility that, thus limited, the operator cannot as satisfactorily or as safely perform his function.

After a rope has been in use for some time, normal wear causes its diameter to be reduced. When this occurs, the shoe 20 and cam member 56 will take a position slightly to the left of that shown in the drawings, and wedge member 62 will move up slightly. This change is, however, accommodated by the lower spring 104 which continues to apply pressure to the locking block 96 after the wedge member 62 has moved up to a new position. Thus the locking block will be maintained in alignment with the key-operated lock mechanism 112. This automatic feature also makes it readily possible to use the rope-locking device with ropes of various diameters without making adjustments to the device.

From the above description, it will be apparent that the present invention provides a rope-locking device which affords many advantages and eliminates serious difficulties encountered with prior devices of this general character. When used to clamp control ropes for flying scenery, for example, the present invention automatically prevents inadvertent release of a rope that carries a dangerously unbalanced tension. When the counterweight system is properly balanced, however, the locking device is easily unclamped from the control rope by a simple foot motion. The present invention also provides means for preventing unauthorized tampering with the rope controls.

Although a specific preferred embodiment of the invention has been set forth in detail, it is desired to emphasize that this is not intended to be exhaustive or necessarily limitative; on the contrary, the showing herein is for the purpose of illustrating the invention and thus to enable others skilled in the art to adapt the invention in such ways as meet the requirements of particular applications, it being understood that various modifications may be made without departing from the scope of the invention as limited by the prior art.

I claim:

1. For use in controlling stage scenery and the like wherein the scenery is manually flown by means of a counterweight system and control rope; an automaticallyoperable safety rope locking device comprising gripping means to frictionally hold the rope, release means operable to disengage said gripping means to permit the rope to be shifted therethrough, and independently operable locking means responsive to an unbalance in tension on 6 said rope for disabling said release means so that said gripping means will maintain friction contact with the rope.

2. Apparatus as claimed in claim 1, including a keyoperated mechanism adapted when actuated to maintain said release means disabled, so as to prevent unauthorized release of said gripping means.

3. An automatic rope lock comprising movable gripping'means to frictionally hold a rope, pressure means normally operable under spring action to produce friction contact between said gripping means and the rope andthereby preventthe rope from slipping, a release mechanism adapted when operated to reduce the pressure produced by said pressure means in said gripping means so that a rope may be shifted therethrough, and locking means responsive to movement of said gripping means resulting from an unbalance in tension on said rope, said locking means including means to block the operation of said release mechanism when the rope tension is unbalanced so that said gripping means will maintain friction contact with the rope.

4. Apparatus as claimed in claim 3, wherein said release mechanism includes movable means to relieve the spring action applied by said pressure means to said gripping means.

5. Apparatus as claimed in claim 3, wherein said pressure means comprises a movable member in contact with said gripping means, and a spring for pressing said member against said gripping means; said release mechanism being operable to shift said movable member away from said gripping means against the action of said spring.

6. Apparatus as claimed in claim 5, wherein said locking means comprises means to secure said movable member in fixed position in response to movement of said gripping means.

7. An automatic rope lock comprising movable gripping means to frictionally hold a rope, a cam member normally urged against said gripping means to produce friction contact between said gripping means and the rope and thereby prevent the rope from slipping, a release mechanism operable with said cam member to reduce the pressure of contact between said cam member and said gripping means so that a rope may be shifted therethrough, and independently operable locking means responsive to movement of said gripping means resulting from an unbalance in tension on said rope, said locking means including means to block the operation of said release mechanism when the rope tension is unbalanced so that said gripping means will maintain friction contact with the rope.

8. Apparatus as claimed in claim 7, wherein said gripping means is formed with cam surfaces engageable with said cam member, said cam surfaces being disposed at a slight angle with respect to the rope axis so that movement of the rope forces said cam member away from the rope; said locking means comprising means responsive to such movement of said cam member and operable to disable said release mechanism when said cam member has been so moved.

9. Apparatus as claimed in claim 8, wherein said locking means includes a wedge member which is normally shiftable in one direction by said release mechanism to relieve the pressure applied to said gripping means, said wedge member being in contact with said cam member and movable thereby in a direction that is transverse to said one direction, whereby to jam said wedge member in position and prevent the release of said gripping means.

10. In a device of the character described, gripping means comprising a pair of clamping members arranged for relative movement towards and away from each other, said gripping means being supported for motion perpendicular to said relative movement, a cam member mounted adjacent one of said clamping members and supported for shifting motion parallel to said relative movement, the adjacent one of said clamping members beingprovided with cam surfaces adapted to produce said shifting motion of said cam member when said gripping means moves perpendicular to said relativemovement, spring-operated pressure means engaged with said cam member to force said cam :member against said gripping means so as normally to press said clamping members together, a release mechanism connected to said pressure means and operable to relieve the force applied thereby to said cam member whereby said clamping members are permitted to move apart, and locking means responsive to the shifting movement of said cam member caused by motion of said gripping means perpendicular to said relative movement, said locking means including means to prevent operation of said release mechanism.

vl1. Apparatus as claimed in claim 10, wherein said release mechanism includes an axially-movable operating rod, a locking block slidably mounted along said operating rod and engageable with said pressure means, and a spring interconnecting said operatingrod with said locking block whereby movement of said rod is normally transmitted through said block to said pressure means to release the grip 'on said rope; saidlocking means including means to prevent movement of said locking block when an unbalanced tension exists in said rope, so that when said operating rod is shifted said spring will be compressed without corresponding movement of said block.

12. Apparatus as claimed in claim'il, including a keyoperated lock mechanism engageable with said locking block to maintain it fixed in position, thereby to prevent unauthorized release of the gripping means.

13. Apparatus as claimed in claim 11, including a foot treadle secured to said operating rod, said foot treadle being positioned to reach the floor when said release mechanism has been fully operated, so that the operator can stand on both feet while manipulating the rope.

, 14. In a device of the character described adapted to clamp a rope secu'rely'to a fixture and operable to release the rope so that the rope may be shifted manually through the device; the combination comprising a pair of clamping members arranged for relative movement towards and away from each other in a direction perpendicular to the longitudinal axis of the rope, said clamping members being adapted normally to tightly grip the rope to prevent it from moving longitudinally with respect to said members; support means forrs'aid clamping members including means to permit said clamping members to be carried a small distance by .said rope in response to an unbalanced tension on the rope; a cam member including a cam follower positioned adjacent one of said clamping members, said cam member being supported for movement in a direction in line with said relative movement between said clamping members, said one clamping member being formed with cam surfaces engageable with said cam follower and arranged to shift said cam member away from said clamping members when said clamping members are moved'by said rope in response to an unbalanced tension thereon; a wedge member supported'for movement parallel to the longitudinal axis of said rope and engageable with said cam member on the side thereof that is remote from said clamping members, said wedge member and said cam member being provided with interchangeable cam faces disposed at an angle with respect to the axis of said rope; spring means normally applying pressure to said wedge member-in a direction. parallel to the axis of said ropesuch that said wedge member transmits a corresponding force through said cam member to said clamping members to cause said clamping members to tightly grip and hold the rope against longitudinal movement; a release mechanism operable to move said wedge member against the pressure applied by said spring means so as to relieve the gripping .force on the rope and thereby permit the rope to be manually shifted through the device; and back-up means positioned adjacent said wedge member on the side thereof that is opposite said cam member, saidback-u-p means and said cam member cooperating to frictio'nally jam said wedge member firmly in position when said cam member has been moved away from said clamping members in response to slight longitudinal movement of said rope due to an unbalanced tension thereon, the jamming of said wedge member between said cam member and said back-up means serving to prevent said release mechanism from moving said wedge member, so that the rope remains tightly gripped by said clamping members whenever an unbalanced tension is applied to said rope.

l5. For use in controlling stage scenery and the like wherein the scenery is manually flown by means of a counterweight system and control rope: an automaticallyopera'ble safety rope locking device comprising, a pair of gripping members having coextensive concave rope gripping surfaces and positioned upon the opposite sides of the longitudinal axis of the rope and adapted to move from a separated position wherein the rope moves freely between themwtowa'rd'each other to a rope-locking position wherein the rope is tightly clamped between said concave surfaces, mounting means for said gripping member'sand providing for movement from arest position in a direction longitudinal of the axis of the rope in response to tension on the rope while the rope is clamped, operating means for imparting relative movement to said gripping members to and from said ropelocking position, and locking means which is rendered operative by the movement of said gripping members longitudinally of the axis of the rope for disabling said operating means whereby said rope cannot be released from its locked position. 3

16. Apparatus as described in claim 15, wherein said mounting means comprises guide means and spring means resiliently holding said gripping members in a normal rest position.

17. Apparatus as described in claim 15, wherein said operating means includes spring means biasing said gripping members relative to each other away from said rope-locking position and wedge cam means operable substantially parallel to the longitudinal axis of the rope to impart relative movement to said gripping means against the action of said spring means.

References Cited in the file of this patent UNITED STATES PATENTS 23,894 Bentley et a1. May 10, 1859 1,482,268 Schopper Jan. 29, 1924 1,580,611 Kirkpatrick Apr. 13, 1926 1,738,215 Thurston et a1. Dec. 3, 1929 1,944,603 Hecker Jan. 23, 1934 FOREIGN PATENTS 789,052 France Aug. s, 1935 

